Joule Thief

[Yucca]

NICE ...  BROS ...


now im a halft to try it ...  i got a cut off wheel some where round here ....

it does sound much similar to the gap in the flyback core .... 

ist

im still trying to find something simple and cheep to hold my horz... electrode ... i wish i never scraped those wire clamps .... they would have been perfect!!!   but it was copper run and i was broke ...  O WELL...

something will come along ...

i have never tryed to cut a feroite core yet ...  i thought it would be a real treat to cut ... but i dont i know never tryed ..  i will today...

ill use a goldmine 5 4 a buck ones ... 1"

ok i just did it ...   10 000 times easyer than i ever thought ... 

i used a drill as my dremel is blowen up ... i worked it a bit hard in the past .... 

cool ist, post results if you find better efficiency with the airgapped core.

[Mk1]

@ist

Find a cd player in the optical box you will find really small neo magnet small enough to fit in the gap of the toroid .

Mark

[Pirate88179]

@ All:

Congratulations to everyone for our 9,000th post!!!

Everyone here has done some very excellent work and, just look how far we have come from the early days.  This topic has also spawned some other topics where the JT circuit is an integral part of those devices, and the information from here has provided new opportunities for further exploration.

If not for the JT circuit, I would not be able to light all of the stuff that I can from my EER.

Anyway, just a quick thank you to everyone for all of the good attitudes and willingness to share information with everyone.

Thank you,

Bill

[sparks]

how about winding a third winding around the entire diameter of the torroid to actively manage the core magnetic circuit.  Just when your core saturates you fire off a pulse in the shield winding which desaturates it very quickly.   Voltage on the output should go way out of sight.  This is a trick I have seen done when a reed switch is up against relay laminations or motor laminations. By actively managing the core the collapse should be real fast. 

[Pirate88179]

Nice circuit xee2, wow 0.25v, very sensitive transistor!

@all
here's an experiment one of you might like to try if you have a spare toroid and time permits.

Take a toroid and cut through it in one spot using a dremel with a cutoff wheel on it.

This will increase core reluctance and should give better performance on a JT because a JT is a simple flyback trafo. There should be considerably less core losses and more power out the windings for the same supply power.

Also it will also allow you to wind say 100+ turns of 32AWG as a third HV output coil easily because you can then just quickly wrap it off the spool inserting each new wrap through the gap without having to thread the whole length for each wrap.

Yucca:

This is a good idea.  We discussed this somewhere a while back (about slicing the toroid) and someone posted a photo of the early radar units and it looked very similar to this approach.

If someone is going to attempt to slice a ferrite toroid, you will need diamond tooling as it is very hard.  (about 9 on the Moh's scale of relative hardness, diamond being 10)  We used to machine ferrite for wave guide applications and I wish I still had a few of those machines and tooling.

Bill